ok, here is the latching schematic i'm using (from Exo):
-this is for model rocketry, so the igniter is a peice of nichrome with some bp on the end (made 'em myself so there is a lot of bp on the end)
-the idea behind this is that i want the thing to ignite when the timer starts to beep, and because it beeps (high low high low) i need a latching circuit to change that into a steady high current which can ignite the igniter. but because i can only have one 9v i need the 9v to power the latching circuit and ignite the igniter. but the transistors take too much away from the current so it can't ignite the igniter just by hooking the igniter where the res. and led are (res. and led are taken out). and the 9v does, alone, have enough current to ignite the igniter.
-i'm tring to fit this all into a altoids container, which is say 4 by 2 inches. the timer and 9v leave only about a 1/2" by 2" for this circuit. i think i can fit it in that area but i need it to work first. (please don't just give up because of the small size, let me be the judge of size and how it will fit in, i can always change things)
the latching circuit is triggered by a the pluses from the timer's speaker, all i need now is to get it send all of the 9v to the igniter so it can ignite the igniter.
igniter is in place of led and R1, all other res values are 1K, but the res with the red arrow next to it is 2K2.